全文获取类型
收费全文 | 896篇 |
免费 | 79篇 |
国内免费 | 311篇 |
专业分类
安全科学 | 65篇 |
废物处理 | 24篇 |
环保管理 | 68篇 |
综合类 | 597篇 |
基础理论 | 252篇 |
污染及防治 | 108篇 |
评价与监测 | 90篇 |
社会与环境 | 51篇 |
灾害及防治 | 31篇 |
出版年
2024年 | 2篇 |
2023年 | 28篇 |
2022年 | 34篇 |
2021年 | 42篇 |
2020年 | 36篇 |
2019年 | 40篇 |
2018年 | 32篇 |
2017年 | 41篇 |
2016年 | 57篇 |
2015年 | 37篇 |
2014年 | 47篇 |
2013年 | 82篇 |
2012年 | 62篇 |
2011年 | 69篇 |
2010年 | 62篇 |
2009年 | 52篇 |
2008年 | 46篇 |
2007年 | 51篇 |
2006年 | 47篇 |
2005年 | 48篇 |
2004年 | 50篇 |
2003年 | 34篇 |
2002年 | 40篇 |
2001年 | 35篇 |
2000年 | 30篇 |
1999年 | 34篇 |
1998年 | 33篇 |
1997年 | 17篇 |
1996年 | 19篇 |
1995年 | 17篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1286条查询结果,搜索用时 15 毫秒
931.
To know the interrelationship between some metals in different ecosystem components (water, sediment, aquatic plant and fish), many samples from these components were collected from four bights at the Nasser Lake, Egypt, and analyzed for Fe, Mn, Zn, Ca, Mg, Pb, Cd, Ni, Co, Cu and Cr using atomic absorption spectrophotometer. Different distribution factors (bioaccumulation factor – BF, discrimination factor – DF and enrichment factor – EF) were applied on the results of analysis. Data showed that the relatively high concentration of measured metals in water samples are derived from fish farms, and discharge of tourism and trade ships. Applying single leaching sequential technique on sediment samples, using different extracting solutions, revealed a strong ability of trace metals to adsorb on or co-precipitate with amorphous Fe/Mn oxides. High concentrations of Fe, Mn, Co and Ni were measured in the intestine while high Cd and Cr concentrations were recorded in the stomach in both Tilapia (nilotica and galilea). Tilapia galilea accumulated high Pb, Cu and Zn concentrations in their stomach, while in nilotica high concentrations of Pb, Cu and Zn were measured in the intestine, liver and muscles, respectively. Myriophyllum spicatum (an aquatic plant) in the lake recorded high concentrations of Fe, Mn and Zn. Bioaccumulation factors of studied elements in the different bights components indicate that the elevated concentration of measured elements in the aquatic plant and Tilapia (nilotica and galilea) are derived from water, reflecting the increase of human activities in Nasser Lake in recent years. However, the present study concluded that all the elements studied were still below the natural back-ground levels, except Zn and Cu. 相似文献
932.
Donatella Desideri Maria Assunta Meli Chiara Cantaluppi Federica Ceccotto Carla Roselli Laura Feduzi 《毒物与环境化学》2013,95(10):1995-2005
Essential and toxic elements were determined by Energy Dispersive Polarized X-Rays Fluorescence Spectrometry (EDPXRF) in the meat of 145 wild and bred animals to provide the baseline data regarding meat of wild and bred animals consumed in central Italy. As far as K, Fe, Ni, Zn, and Cu are concerned, no significant differences resulted between young and adults and between males and females for farmed and wild animals. No marked differences were found between hunted and non-hunted animals groups. In all samples analyzed, Mn, Cr, and Mo were below the detection limit. As far as the non-essential or toxic elements are concerned, As, Cd, V, and Hg concentrations in muscle from wild and bred animals were low and always below the detection limits. Among the wild animals killed with lead (Pb) bullets, elevated Pb concentrations in tissues were detected. This finding may result in elevated Pb levels in meat ingested by humans. 相似文献
933.
利用Landsat遥感数据定量研究了淮河流域1995—2007年间各湿地类型的规模变化,分析了其变化特征,辨识了湿地消长的热点区域,并研究湿地变化热点空间分异的影响因子。结果表明,研究期间流域内水田、库塘等人工湿地大幅增加(净增量分别占1995年湿地总面积的16.81%、4.57%);湖泊、沼泽等自然湿地则明显减少(净减少量分别占1995年湿地总面积的1.06%、2.79%),且多转为人工湿地。湿地变化热点多分布于流域东部及南部;人工湿地变化热点分布连续而集中,自然湿地变化热点则稀少而分散。高程和气温对人工湿地增长热点及自然湿地减少热点的发生影响强度相对较高;社会经济与可达性因素对热点的发生具有显著作用,但其影响强度相对较弱。整个淮河流域,湿地变化热点的发生受多种要素的耦合作用,但湿地变化热点空间分异的首要因素是流域自然地理等背景条件的约束作用。 相似文献
934.
Diet is the major route of exposure to contaminants, therefore food monitoring programs are essential to estimate the degree of human risk. We present a study undertaken in Austria dealing with the total uptake of mercury, cadmium, arsenic and lead. The dates were calculated from diet as well as from commercial food. Higher contaminated foodstuffs are registered and a comparison was made between body burden of babies and adults on the basis of bodyweight. It was pointed out, that cooked or washed food ready to eat has a lower burden of lead and cadmium than non prepared food due to household processing, which may decontaminate food to some extent’ Arsenic content was not reduced, because it is bound chemically and not primarily deposited on the surface of food such as in the case of lead. It was mentioned that the type of compound plays an important role in the assessment of action of those elements on humans. Their biological activity is not necessarily related to their concentration in food. As in the case of selenium and chromium one has to take into consideration that there is a narrow range between benefit and harm, toxicity, and minor supply. Therefore we conclude, that due to interactions of elements, their different biological activity and due to the difference of compounds present in food, we have to relativate the terms toxicity and essentiality. Then we can get a more profound insight into the problems of trace elements in food. 相似文献
935.
R. Djingova I. Kuleff S. Arpadjan S. Alexandrov A. Voulgaropoulos T. Sawidis 《毒物与环境化学》2013,95(3):149-158
NAA and AAS have been applied to determine the content of As, Br, Ca, Cd, Co, Cr, Cu, Fe, K, La, Mn, Na, Ni, Pb, Sb, Sc, Sm and Zn in Ulva lactuca and Gracilaria verrucosa from Thermaikos Gulf, Greece. The analytical data has been subjected to cluster and stepwise discriminant analysis. Thus the influence of some industrial sources on the pollution of water in the Gulf is detected and correlation between Zn‐Co‐Cr‐La; Br‐K; Cu‐Ni; Cd‐Sb‐Mn in the investigated algae is established. 相似文献
936.
Various elements and inorganic ions in rice straw and ash samples were analyzed by using inductively coupled plasma atomic emission spectrometry (ICP‐AES) and ion chromatography (IC). Five major elements: Mg, Mn, Al, Ca, and Fe and eight minor and trace elements: Cr, Cu, Ti, Zn, La, Sr, Ba, and Hg were detected in these samples, at more than ppm‐level. In ash samples the trace elements such as Y, As, V, Se, and Sc were also identified. The concentrations of SO4, PO4, Cl, Na, and K ions in these samples were higher than those of other ions measured. These elements and inorganic ion concentrations were approximately one order of magnitude higher in the ash than in the straw samples. Gas chromatography/mass spectrometry (GC/MS) and library search showed the presence of fatty‐, carboxylic‐ and nicotinic acids, and their derivatives in small quantities in the straw samples. 相似文献
937.
Pollution of hazardous elements in roof runoff has been a potential danger to aquatic ecosystem as documented in previous studies. In this study, concentrations of lead (Pb), zinc (Zn), arsenic (As), and cadmium (Cd) in roof runoff were measured for short-term rainfall events. The concentrations of the selected elements varied to a high degree during the rainfall period, and the well-known first-flush phenomenon was not observed due to the short-term rainfall patterns. Based on event mean concentrations (EMCs) and fluxes, the elemental pollution may be ranked as Zn >> Pb > As > Cd. The average levels of Pb and Zn exceeded the fourth class value and fifth class value of the environmental quality standards for surface water in China. The relative high pollution could be caused by atmospheric deposition and the erosion of crust steel appurtenance installed above the rooftop. Furthermore, elements in particulate form dominated the roof runoff pollution, and the ratios of elements in particulate form to total amounts were 0.6 (As), 0.9 (Pb), 0.7 (Cd), and 0.5 (Zn). This study cleared the pollution characteristics of hazardous elements in short-term storm water roof runoff; it was useful for the selection of best management practices. 相似文献
938.
Michelle Graymore Graeme Allinson Mayumi Allinson Frank Stagnitti Yasuyuki Shibata Masatoshi Morita 《毒物与环境化学》2013,95(3-4):427-439
The transport of the s‐triazine herbicide, atrazine, through the red, calcareous earth soils of the South Australian Riverland was investigated. Small, undisturbed soil cores were extracted from the inter‐row topsoil of a vineyard adjacent to the River Murray, approximately 10 km south‐west of Overland Corner, South Australia. The vines were grown in a deep (1–4 m) reddish brown, strongly alkaline, sandy loam with a low organic carbon content (<2%). Atrazine concentrations in the leachate were dependent on application rate and soil type. High application rates on subsoil gave high rates of leaching for a longer time compared to the same application rate on topsoil and/or lower application rates on either topsoil or subsoil. Overall, 37–65% of the applied atrazine was detected in the leachate from subsoil cores, 14–25% in topsoil core leachates. Small amounts of atrazine (< 10% of applied dose) were found only in the top 2 cm of the core profiles. The results suggest that this herbicide is somewhat mobile in such strongly alkaline, sandy loam soils and that the irrigated soils of this region are likely to be prone to leaching of atrazine, and therefore that groundwater supplies in this area may be at risk of contamination through use of triazine herbicides. 相似文献
939.
Carla da Silva Carneiro Eliane Teixeira Mársico Edgar Francisco Oliveira de Jesus Roberta de Oliveira Resende Ribeiro Renata de Faria Barbosa 《Chemistry and Ecology》2013,29(1):1-8
Trace elements were determined in fish and oysters from Sepetiba Bay, Brazil, by total reflection Xray fluorescence using synchrotron radiation (SRTXRF). Cr, Mn, Fe, Ni, Cu, Zn and Se were determined in fish muscles and organs and in oyster soft tissue. SRTXRF was shown to be a good tool for the analysis of trace elements from biological tissue samples. Overall, the levels of the analysed metals were higher in oysters than in the fish samples. Metals were not uniformly distributed throughout the body of the analysed fish. The detected concentrations of Cr, Zn and Se were very high in some samples, surpassing the maximum limits established by Brazilian legislation. 相似文献
940.